1. Field of the Invention
The invention relates to the field of character recognition systems, U.S. Class 340/146.3.
2. Prior Art
There is a continuing demand for character recognition systems, particularly those which are able to discern ordinary printed alpha-numeric symbols. The most common approach to character recognition compares, in a two-dimensional array, the viewed characters with predetermined forms. Often this comparison proceeds by examining predetermined areas of the viewed character to determine if they are dark or light. This two-dimensional, sectional analysis is shown graphically in U.S. Pat. No. 3,964,022, FIGS. 9a-9f. This particular system employs a 32.times.32 self-scanned, photodiode array. The video data is digitized and then stored in an appropriate memory. One problem with this type of system is that in addition to requiring large memory storage, it attempts to handle all the information for a particular character at one time. That is, the entire two-dimensional array is considered at one time. This results in poor utilization of circuitry.
In U.S. Pat. No. 3,873,972 another character recognition system is disclosed. In this case, a linear array is employed for scanning the characters as shown in FIG. 2. However, the video information from this array is accumulated in the scratch-pad memory 42. Then both horizontal and vertical features are detected and used to identify characters. Thus, even though this system employs a linear array, it is again a two-dimensional matrix approach which also stores unprocessed video.
As will be described, with the invented apparatus and method the raw video data is not stored, but rather is analyzed as it is read from the linear array. The recognition of characters is done more in a "pipeline" manner which permits better utilization of the circuitry when compared to prior art approaches.